Chain saw with a stopping device

A portable power-operated tool, particularly a portable chain saw, comprising a housing;

• a prime mover carried by said housing and having a rotary output member;
• means for starting said prime mover;
• manually operable means for normally blocking the operation of said starting means;
• a rotary tool driving member;
• a wrap spring clutch interposed between said members to rotate said driving member in response to rotation of said output member, said clutch including a first component which is driven by said output member to rotate in a predetermined direction in response to rotation of said output member, a second component which drives said driving member, and a prestressed coil spring surrounding and normally frictionally engaging said components, said coil spring having convolutions surrounding said components in such orientation that the spring tends to reduce its diameter, to bear against said components and to be driven by said first component due to the prestressing thereof;
• means for disengaging said clutch including a manually displaceable disengaging element on said housing, said clutch further including means for braking said driving member in response to displacement of said disengaging element so that the driving member is braked substantially simultaneously with the interruption of transmission of torque thereto, said spring including or constituting said braking means and being disengageable from at least one of said components in response to displacement of said disengaging element, said disengaging means further including means for interrupting the rotation of said spring with said one component in response to displacement of said disengaging element, said spring comprising a portion which extends from said first component and said interrupting means comprising a stop which is engageable with said portion of said spring in response to displacement of said disengaging element to thereby prevent the spring from rotating with said first component;
• and means for engaging said stop with said portion of said spring in response to blocking of the operation of said starting means by said blocking means, said stop including a reciprocable decoupling element and said engaging means including means for biasing said decoupling element to a position in which said decoupling element extends into the path of movement of said portion of said spring, said disengaging means having retracting means for normally maintaining said decoupling element away from the path of movement of said portion of said spring, said retracting means comprising a retracting lever having a first arm cooperating with said disengaging element and a second arm cooperating with said blocking means, said disengaging element comprising a guard for the hand holding said housing and being pivotable with reference to said housing between a first position in which said clutch is engaged and a second position in which said clutch is disengaged, said guard having a seat and said first arm having a portion engaging said seat in the first position of said guard, said guard being pivotable to the second position by the hand holding said housing to thereby disengage said seat from said first arm whereby said biasing means is free to move said decoupling element into the path of movement of said portion of said spring.